Move include/malloc.h to include/gpxe/malloc.h, since everything in there

is now gPXE-specific.  (The standard malloc() et al have been in stdlib.h
for a while).

Add free memory counter.

src/include/gpxe/malloc.h

@@ -0,0 +1,57 @@
+#ifndef _GPXE_MALLOC_H
+#define _GPXE_MALLOC_H
+
+#include <stdint.h>
+
+/** @file
+ *
+ * Dynamic memory allocation
+ *
+ */
+
+/*
+ * Prototypes for the standard functions (malloc() et al) are in
+ * stdlib.h.  Include <gpxe/malloc.h> only if you need the
+ * non-standard functions, such as malloc_dma().
+ *
+ */
+#include <stdlib.h>
+
+extern size_t freemem;
+
+extern void * alloc_memblock ( size_t size, size_t align );
+extern void free_memblock ( void *ptr, size_t size );
+extern void mpopulate ( void *start, size_t len );
+extern void mdumpfree ( void );
+
+/**
+ * Allocate memory for DMA
+ *
+ * @v size		Requested size
+ * @v align		Physical alignment
+ * @ret ptr		Memory, or NULL
+ *
+ * Allocates physically-aligned memory for DMA.
+ *
+ * @c align must be a power of two.  @c size may not be zero.
+ */
+static inline void * malloc_dma ( size_t size, size_t phys_align ) {
+	return alloc_memblock ( size, phys_align );
+}
+
+/**
+ * Free memory allocated with malloc_dma()
+ *
+ * @v ptr		Memory allocated by malloc_dma(), or NULL
+ * @v size		Size of memory, as passed to malloc_dma()
+ *
+ * Memory allocated with malloc_dma() can only be freed with
+ * free_dma(); it cannot be freed with the standard free().
+ *
+ * If @c ptr is NULL, no action is taken.
+ */
+static inline void free_dma ( void *ptr, size_t size ) {
+	free_memblock ( ptr, size );
+}
+
+#endif /* _GPXE_MALLOC_H */